Earthwatch Interview: Dr. Aurélie Cohas
Dr. Aurélie Cohas is Assistant Professor at the Laboratory of Biometry and Evolutionary Biology, University of Claude Bernard in Lyon, France. She heads up Earthwatch project Of Mountains and Marmots: Climate Change in the French Alps.
Earthwatch’s Rob Stringer caught up with her to find out how she first became interested in one of the Alps’ most iconic and appealing mammals, and how her research is shedding light on the ways in which marmot societies are likely to be impacted by a changing climate.
Join an Earthwatch expedition this summer and observe the behaviour of alpine marmots in the French Alps
Q. You have worked with marmots for over ten years. How did you first become interested in them?
I was born very close to the French Alps, so I have always been familiar with marmots. It’s very easy to see them in this area. When you enjoy hiking and being in the mountains, they become like your best friends! Later on, I studied biology, and knew that I wanted to work with animals and study their behaviours, and I found that marmots are an amazing species to work with. They are social animals – meaning that they interact with individuals of the same species in a cooperative way. Marmots offer unique opportunities to answer such intriguing and highly-debated question like why sociality evolved.
Q. What is the focus of your research?
Our research questions relate to climate change, and investigate which species in the research area will be able to cope, or not cope with it, and what characteristics will make them able to cope or not to cope with it. We’ll use the marmot as a model species. We already have some hints that climate change is starting to adversely affect marmots in this very high altitude location. The whole alpine ecosystem is really under threat. All the species living there have no chance to relocate elsewhere, because they are so highly adapted to their environment. When climate conditions start to change, this presents quite a big challenge.
Q. Why is it important to run this project now?
We are building on very detailed data about physical traits such as individuals’ weight or size for example, and also some fitness data, such as how many offspring are produced every year or survival rate from one winter to the other. With this data we are able to address questions that are really relevant at this time. It is getting more and more difficult to run long term studies like this despite their huge scientific value. Having Earthwatch volunteers involved in this research, it becomes much more likely to keep going over many years.
Q. What do we already know about marmots?
We know quite a lot about marmots from a physiological point of view, as there has been quite a lot of study in this area. For instance, there is a lot of work being carried out in America (on closely-related species) investigating how marmots are able to put weight on and lose a lot of weight very easily. We also understand marmot behaviour quite well now, especially how they are organised in their groups. Now we are interested in looking at their general ecology, and especially their demography: that is how marmot numbers fluctuate and what drive these fluctuations.
Q. One activity that Earthwatch volunteers will take part in will be catching marmots! How easy are they to catch?
Capturing a marmot is not that easy. They are clever and can learn lots of tricks, so you need luck on your side. You have to know the animals very well and learn to read their signs. First you need to know where their territories are - to know where the main burrows are, where the animals spend most of their time, and the tracks they use the most.
Then, you need to have a good trap, and find some food the marmots really like. (The only thing they care about is dandelion. They have no taste for peanut butter, fruit, honey etc.) Then you need a bit of patience, and a hungry marmot passing by the traps. Sometimes you face a very clever one that uses all the tricks to get the bait without being trapped. Once caught, we then transfer the marmot to a special bag. They see a big black hole, and they go in thinking it will lead to the safety of their burrow!
Marmots are not aggressive. They are really easy to work with. Although when they whistle in your ear it is quite awful! It sounds like a whistle, but it’s really a sort of bark. They do this mainly to alert other marmots to what is going on.
Q. Your research cites the findings of Prof. Tim Clutton-Brock, who leads Earthwatch project Meet the Meerkats of the Kalahari. Does the work carried out on your project complement his, and vice versa?
Every behavioral ecologist would like to be as well-renowned as Tim Clutton-Brock! Our work is in many ways similar since we are both working on a social species and on questions linked to the evolution of sociality. At first sight marmots and meerkats seems quite similar, they actually show striking differences.
For instance, both meerkats and marmots have a dominant female in a group. All the other individuals in the group are just there to ‘help’. Dominant females will try to suppress the reproduction of the female subordinates present in the group. They do this by agitating the subordinates, which lowers their levels of reproductive hormones and increases levels of stress hormones, making them unable to conceive or carry a pregnancy to full term.
It seems that this suppression is very efficient in marmots. Subordinates rarely conceive young, and in only two cases (over 20 years of study and 24 families followed each year) we had subordinates females that managed to raise offspring. In meerkats however, it seems to be less efficient, and some subordinate females regularly manage to raise young to independence.
In terms of research, Prof. Clutton-Brock and I are interested in the same big questions, such as, what determines group size? These similarities and differences help us to assess the generality of our findings and to find general rules. However, for the marmot project, we are more interested in the marmots’ interaction with their environment and on how sociality can help the marmots to cope with the severity of the environmental conditions they are facing. It is the kind of research that has not yet been carried out in much detail with meerkats.
Q. What are you most excited about for this project?
I really like to share! I usually have quite a big team. I really enjoy being in the field because the best way to share with people is to make them part of your work. Once people start to get involved they really want to know more. They want to make progress in the project, and put their own stamp on it, and I think this is good. You cannot keep science for the scientists only.
Q. Apart from marmots, what animals is a volunteer likely to see?
In summer the people mostly come for the wildlife because it is incredible. You can see every alpine animal close up, and they are not scared of humans at all. We see all the big ones – such as the ibex and the chamois. You can also see foxes. (When the marmots start whistling, you know the foxes are around!).
Also, for a birdwatcher, it’s a dream. You have the golden eagle, and the bearded vulture, and we have also some other quite rare and colourful species like the rufous-tailed rock thrush... And of course there are marmots everywhere!
Just above the marmots there is a summit called La Grande Sassière. It’s fairly easy to go to, and from there you can see everything. You can see from Mont Blanc to all the Vanoise summits. Being there in the morning at sunrise is incredible!
- The alpine marmot is the third largest rodent mammal in the world, after the capybara and the beaver.
- Marmots are exceptional diggers, and able to excavate solid earth that even a pickaxe may struggle with. Even more amazingly, they use their mouth to dig, and their legs only to remove the soil.
- Alpine marmots used to be hunted because it was believed that rubbing their fat on a person’s skin could help cure rheumatism.
- Marmots hibernate for 200 days per year from the beginning of October to the beginning of April. During hibernation, they have long phases of hypothermia (the sleeping phase), and short phases of euthermia, (the waking up phases). During hypothermia, their temperature, which is usually around 38 to 40°C, can drop to a minimum of 5°C. Their heart rate drops from 180-200 beats per minute to 28 per minute, and their respiratory frequency drops to 1 to 2 inspirations per minute.
- Marmots lose around 30% of their weight during hibernation.
- The alpine marmot had disappeared from the Pyrenees at end of the Pleistocene epoch (about 10,000 years ago) due to an increase in temperature. Between 1948 and 1988, they were successfully reintroduced to the area by the French government. And guess where these marmots came from? From the Vanoise, where the project is located! The Earthwatch research team is working in close collaboration with scientists working in the Pyrenees.
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